Anatomical simulators have been developed for training and assessment of medical students, nursing students, medics and practitioners. These simulators have enabled health care professionals of all backgrounds to practice clinical procedures in a safe environment, away from the patient. The majority of simulators that have been developed thus far focus mainly on emergency care, anesthesia and laparoscopic surgery. In addition, simulators have been developed for examination of body cavities, as described in U.S. Pat. No. 6,428,323, the disclosure of which is incorporated herein by reference.
In simulators where direct or indirect manual contact is required to practice an examination or procedure, performance evaluation is usually handled in the following ways: 1) performance is not measured or assessed; 2) performance is assessed in a summative fashion and simply marked as complete or incomplete; or 3) performance is measured by placing sensors on the instruments, in which case, the path of the instrument is recorded but the effect of the instrument on an organ or body surface is not measured.
Two examples of medical procedures that combine direct and indirect contact are endotracheal intubation and needle biopsy or aspiration. Both procedures have potentially serious complications if not done correctly. For intubation, an endotracheal tube is inserted in the patient's airway to maintain an open passage and allow air to pass freely to and from the lungs for ventilation. The most feared complication, usually due to operator experience or patient anatomy is a ‘missed intubation’ or inability to insert the endotracheal tube into the airway. Even if successful, potential complications that may occur during intubation include injury to the teeth, lips and oral cavity; edema; bleeding; tracheal and esophageal perforation; pneumothorax (collapsed lung); and aspiration. Further life-threatening complications of airway problems may occur and these signs and symptoms include, but are not limited to, sore throat, pain or swelling of the face and neck, chest pain, subcutaneous emphysema, and difficulty swallowing.
Needle biopsy or aspiration also has risks. A recent study showed that in one case a needle biopsy of a liver tumor resulted in major bleeding. Other complications depend upon the body part on which the biopsy takes place: Lung biopsies are frequently complicated by pneumothorax (collapsed lung). This complication can also accompany biopsies in the upper abdomen near the base of the lung. About one-quarter to one-half of patients having lung biopsies will develop pneumothorax. A small percentage of patients will develop a pneumothorax serious enough to require hospitalization and placement of a chest tube for treatment—a procedure, which also requires simultaneous use of direct and indirect contact. Although it is impossible to predict in whom this will occur, collapsed lungs are more frequent and more serious in patients in whom the biopsy is difficult to perform. Breast biopsies may also be complicated by pneumothorax. For biopsies of the liver, bile leakages may occur. Pancreatitis (inflammation of the pancreas) may occur after biopsies in the area around the pancreas. Deaths have been reported from needle aspiration biopsies, but such outcomes are extremely rare.
Performance of other medical procedures could improve with improved training devices. For example, inserting a needle or catheter into a central line or arterial line typically requires palpation and can be for femoral, subclavian, jugular arteries and the central venous system. For another example, a central venous catheter (CVC or central venous line or central venous access catheter) is a catheter placed into a large vein in the neck, chest or groin, this is inserted by a physician when the patient needs, for example, frequent or intensive cardiovascular monitoring, for assessment of fluid status, and for increased viability of intravenous drugs/fluids. The most commonly used veins are the internal jugular vein, the subclavian vein and the femoral vein. This is in contrast to a peripheral line which is usually placed in the arms or hands. The Seldinger technique is generally employed to gain central venous access. Examples of these devices include Hickman catheters, which require clamps to make sure the valve is closed, and Groshong catheters, which have a valve that opens as fluid is withdrawn or infused and remains closed when not in use.
Ultrasound has become an important tool for guidance of instruments or needles inserted into a cavity. Ultrasound is frequently used in the placement of internal jugular vein catheters. The ultrasound has a transducer that is applied to the surface and a needle is inserted into the vein or artery.
Vaginal ultrasound involves external palpation and insertion of devices. Pressure is typically put on the abdomen during vaginal ultrasound. Transvaginal ultrasound is a method to look at a woman's reproductive organs, including the uterus, ovaries, cervix, and vagina. The procedure comprises a patient lying on a table with knees bent and feet in holders called stirrups. The health care provider places a probe, called a transducer, into the vagina. The probe is covered with a condom and a gel. The probe sends out sound waves, which reflect off body structures. A computer receives these waves and uses them to create a picture. The doctor can immediately see the picture on a nearby monitor. The health care provider moves the probe within the area to see the pelvic organs and sometimes puts pressure on the abdomen.
Childbirth, with and without complications, such as breach and/or shoulder dystocia, involves exterior palpation and insertion of devices or instruments. For example, the McRoberts maneuver has proven effectiveness in the management of shoulder dystocia. This procedure results in a cephalad rotation of the symphysis pubis and a flattening of the sacral promontory. These motions push the posterior shoulder over the sacral promontory, allowing it to fall into the hollow of the sacrum, and rotate the symphysis over the impacted shoulder. When this maneuver is successful, the fetus should be delivered with normal traction. The McRoberts maneuver alone is believed to relieve more than 40 percent of all shoulder dystocias and, when combined with suprapubic pressure, resolves more than 50 percent of shoulder dystocias.
Rotation maneuvers may require episiotomy to gain posterior vaginal space for the physician's hand. The Rubin II maneuver consists of insetting the fingers of one hand vaginally behind the posterior aspect of the anterior shoulder of the fetus and rotating the shoulder toward the fetal chest. This motion will adduct the fetal shoulder girdle, reducing its diameter. The McRoberts maneuver also can be applied during this maneuver and may facilitate its success.
Examination for a hernia typically involves palpation of exterior and interior anatomy. In a patient with a large hernia, physical examination reveals an obvious swelling or lump in the inguinal area. In the patient with a small hernia, the affected area may simply appear full. Palpation of the inguinal area while the patient is performing Valsalva's maneuver confirms the diagnosis. To detect a hernia in a male patient, the patient is asked to stand with his ipsilateral leg slightly flexed and his weight resting on the other leg. The examiner inserts an index finger into the lower part of the scrotum and invaginates the scrotal skin so the finger advances through the external inguinal ring to the internal ring (about 1½″ to 2″ [4 cm to 5 cm] through the inguinal canal). The patient is then told to cough. If the examiner feels pressure against the fingertip, an indirect hernia exists; if pressure is felt against the side of the finger, a direct hernia exists.
Use of an EEA stapler for end-to-end anastomosis to preserve the anal sphincter typically requires external palpation during the insertion of the EEA stapler into the patient's rectum.
Thus, almost all areas of medicine, including, but not limited to, anesthesia, gynecology, obstetrics, radiology, surgery, and orthopedics, involve procedures benefitting from simultaneous external and internal contact.
Healthcare training is an iterative process and must include opportunities to practice various clinical skills. One of the most important aspects of clinical training is assessment. Assessment allows learners to gauge their level of understanding or performance as compared to their colleagues or a pre-determined standard. Appropriate feedback is critical to mastering hands-on clinical skills. Medical training is the only defense in decreasing clinical errors. Thus, simulators that enhance the training of practitioners for procedures involving direct and indirect contact are desperately needed. Simulators that can reliably and accurately provide feedback to a practitioner as to the quality of their performance are also desirable.